H.D.
Take him to Half Priced Books. =) They usually have a wonderful childrens section. Let him pick out ANY 2 books he wants. Tell him that when he is finished reading then he can come back and do it again. You can find books for a $1 in their clearence section. We make an event of it, lunch and HPB! If you make reading a chore it will BE a chore, make it something fun to look forward to. =)